[In connection with the comparison here instituted by M. Pasteur between the drinking and keeping qualities of the two kinds of beer, it may be useful to draw the reader’s attention to a review by Dr. Charles Graham of the French edition of this work, published in _Nature_ for January 11th, 1877, page 216. At the same time we must remark that Dr. Graham appears to have overlooked M. Pasteur’s footnote, page 12, English edition:—“His assertion, that by bottom fermentation store beers can be produced, whereas those produced by top fermentation must be consumed at once and cannot be transported, are certainly strange to an Englishman. So far from these unfavourable comparisons being true in all cases, the exact opposite is generally the case. Bavarian and other bottom fermentation beers are in fact those which can neither be preserved nor transported without the liberal employment of ice; even that sent from Vienna to London must be kept cold artificially, in order to avoid rapid destruction. As regards flavour, there are many who think a glass of Burton pale ale, or of good old College rent ale, to be superior to any Bavarian beer. The chief cause of the decline in the production of top fermentation beers on the Continent has been the want of attention in the fermentation process; whereas the English brewer, especially the brewer of high-class ales, has been unremitting in his attention to the temperature in fermentation and to the perfect cleansing of the ale. Now, where such attention is given, it is not difficult to obtain ales which will keep a few years. While objecting to our English produce being so hastily depreciated by M. Pasteur, our brewers will be the first to avail themselves of his biological researches, in order to render their produce more stable and better flavoured, without having recourse to the general adoption of the vastly more costly system of bottom fermentation.”—D. C. R.] Footnote 12: To preserve bottled beer from deterioration, some bottlers employ, at the moment of filling, a small quantity of bisulphite of lime. Others heat the bottles to a temperature of 55° C. (131° F.) In the north of Germany and in Bavaria, this practice has been widely adopted since the publication of the author’s “Studies on Wine,” and some of M. Velten’s writings. The process has been termed _pasteurization_ in recognition of the author’s discovery of the causes of deterioration in fermented liquors, and of the means of preserving such liquors by the application of heat. Unfortunately this process is less successful in the case of beer than in that of wine, for the delicacy of flavour which distinguishes beer is affected by heat, especially when the beer has been manufactured by the ordinary process. This effect would be less felt in beer manufactured by the process which is advocated in this work. Footnote 13: